Pond Boss Forums INTRO Questions & Observations Sealing a leak in my new dam

I just completed my small dam and installed the overflow piping system. The water began to rise immediately but after two days, it stopped rising at about 2 feet around the overflow pipe.upon examination today, I see there is a small stream of water coming out from or around the pipe at the back of my dam.
My overflow system is a 12" coorugated black pipe that runs through my dam at the bottom of it. Inside my dam, I inserted a 10" black corrugated pipe inside the 12"pipe and turned both up to a 90 degree elbow, sealing their junction with silicone and tile tape. The water level is to be at the top of the 10" upturned pipe's end.
How can I stop this leaking around the 12" pipe ? Thanks!

If you didn't install anti-seep collars around the pipe, and compact the pipe and collars in with suitable clay, you probably cannot stop the flow. You would need to start over, dig it up, and install the collars.

I wouldn't use the corrugated black pipe going through the dam if you needed to attach more than one piece together because of the potential of leaks. I'm assuming that you didn't use any anti-seep collars around the pipe either. There is no good way to seal 2 pieces together, it's a clamshell type of connection that you use zip ties to hold together. That type of connection has no seal or gasket. You tried to use silicone seal to "glue" it to the pipe, but due to the plastic being smooth, the silicone doesn't have any "bite" to stick both pieces together, and it has no solvent to melt the two pieces together.

At this point in the project, I'd drain the water down below the pipe, dig out the pipe and install solid wall belled end with a gasket pipe or solid glue in place pipe. But to glue the pipe you will need to push it together with earthmoving equipment because it will want to push back apart while the glue sets up.

At this point of the project it won't cost much to do vs. waiting until the pond is full and you have fish in there.....

Don't forget proper compaction around the pipe and anti-seep collars.

Or, if you have enough fall behind the dam, dig the pipe out, compact the trench with clay and use a siphon system.

I would not guarantee this to work, but you could encase the joint completely in concrete before covering and compacting it. Good high strength concrete will hold water and the corrugated pipe would give it a good chance to seal.

Best bet is replace the pipe with a smooth solid pipe. Gasket type if it has to be joined in more than one section.